sts-suite

Terminal debugger for Feetech STS3215 smart serial bus servos.

Requirements

• Python 3.10 or newer
• A USB-to-TTL adapter wired to the servo bus

Install

With uv:

uv tool install sts-suite

Or with pip:

pip install sts-suite

Run

sts

Pick a serial port and baud rate. The debugger opens. The last choice is saved to ~/.cache/sts-suite/last.json.

If no motors respond, hit Baud sweep in the port picker and it will try every preset and pick the one with the most motors.

Main screen

Left sidebar: motors on the bus. Toggle multi-select with ctrl+space; goal and nudge then drive the whole selection via sync_write in one packet.

Right side: a watch strip with the always-visible vitals, then the full register table. Enter on any RW row pops an edit modal with a description, range, units, and a dropdown for enum registers.

Screens

Keybindings

Modes

The control bar adapts to the selected motor's mode register.

Status register

Bit flags decoded in the register table and watch strip.

Snapshot file

s writes sts-state-YYYYMMDD-HHMMSS.json in the current directory with every register value for every motor on the bus. Load one with d to diff against the current live readings.

Preset file

Presets live in any JSON file with a top-level registers map:

{
  "registers": {
    "p_coefficient": 32,
    "i_coefficient": 0,
    "d_coefficient": 0,
    "torque_limit": 800,
    "acceleration": 30,
    "max_temperature_limit": 70
  }
}

Ctrl+L applies every RW field to the selected motor; EEPROM fields are unlocked and re-locked automatically.

Performance

• Live tick reads SRAM 40-70 in one read_raw_data call (single round trip per refresh).
• Full refresh reads EEPROM 0-39 plus SRAM 40-70 as two bulk reads instead of 26.
• Serial I/O runs in a worker thread; a stuck motor can't freeze the UI.
• Multi-motor writes use sync_write_raw_data so N motors update in one packet.

Stack

• Textual and textual-plotext for the UI
• rustypot for the Feetech protocol over serial

License

Apache License 2.0. See LICENSE.